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US4981549A Expired / Lapsed US ⏱️ 0.0 years remaining

Method and apparatus for growing silicon crystals

Assignee: Mitsubishi Materials Silicon Corp
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Filing: 1989-02-22
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Granted: 1991-01-01
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Expires: 2009-02-22
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Abstract

Abstract A silicon single-crystal growing method is disclosed which immerses a seed crystal in a silicon melt and pulls the seed crystal from the melt to thereby grow a silicon single-crystal, and in which the dwelling time of the silicon single-crystal, which is being pulled in a temperature range of between 1,050 DEG to 850 DEG C., is set to be no longer than 140 min. The apparatus suitable for practicing the above method has a crucible, a pulling mechanism, and a temperature control shell. The temperature control shell is located above the crucible for cooling said silicon single-crystal at a cooling rate such that the dwelling time of said silicon single-crystal, which is being pulled in a temperature range of between 1,050 DEG to 850 DEG C., is not longer than 140 min.

Inventors

  • 👤 Ichiro Yamashita
  • 👤 Koutaro Shimizu
  • 👤 Yoshiaki Banba
  • 👤 Yasushi Shimanuki
  • 👤 Akira Higuchi
  • 👤 Hisashi Furuya

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 06:24
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; C30B15/00; C30B15/20; C30B15/206; Y; Y10; Y10S; Y10S148/00; Y10S148/003; Y10S148/071; Y10T; Y10T117/00; Y10T117/10; Y10T117/1024; Y10T117/1032; Y10T117/1068

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 84 words
In the method of growing silicon single-crystals by the Czochralski technique which comprises the steps of immersing a seed crystal in a silicon melt and pulling said seed crystal from said melt to thereby grow a silicon single-crystal, the improvement which comprises: (a) initially cooling the silicon single-crystal to 1,050° C., (b) cooling the silicon single-crystal from 1,050° to 850° C. in no more than 140 minutes, and (c) cooling the silicon single-crystal from 800° to 600° C. in no less than 120 minutes.
Claim 2
Dependent Claim 84 words
In the method of growing silicon single-crystals by the Czochralski technique which comprises the steps of immersing a seed crystal in a silicon melt and pulling said seed crystal from said melt to thereby grow a silicon single-crystal, the improvement which comprises: (a) initially cooling the silicon single-crystal to 1,050° C., (b) cooling the silicon single-crystal from 1,050° to 850° C. in no more than 140 minutes, and (c) cooling the silicon single-crystal from 800° to 600° C. in no less than 120 minutes.

References Cited (Backward Citations)

US4661166A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1993-12-31 1994-07-02 1995-01-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1997-12-31 1998-07-02 1999-01-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2001-12-31 2002-07-02 2003-01-01 $7700.00 Window Closed / Lapsed

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